The present invention relates to electrically-driven brushes of the type including a plurality of bristle holders which are driven by an electrical motor contained within the brush. The invention is particularly useful in toothbrushes, and is therefore described below with respect to this application.
A large number of different types of electrically-driven toothbrushes have been developed and are commercially available. Examples of known electrically-driven toothbrushes are described in U.S. Pat. Nos. 3,242,516, 4,156,620, 4,827,550, 4,845,795, 1,947,324, 3,115,652 and 4,274,173. However, efforts are continuously being made to increase the brushing efficiency of such toothbrushes.